In the text about the Petrova bloodline it says Nadia probably had a kid to continue the bloodline, but Katherines unnamed sister could’ve had a kid and continued the bloodline, correct. I don’t think that the doppelgänger has to have the kids to continue the bloodline except Amara and Tatia, bc they were the only living Petrova family members able to bear kids. But Mr. and Mrs. Petrova had 2 kids. One doppelgänger one not. So, couldn’t have the sister have had a kid to continue the bloodline?